Plant tissues (leaf and root) were sampled after 0, 0.5, 1, 2, 4, 7, and 12 h after treatments initiated. Severe drought stress plants were sampled 0, 4, 12, 24, 36, 48, and 60 h after reaching 40% of soil moisture content.
Total RNA was isolated from 0.1 g (approximate fresh weight) of sampled soybean seedlings using a Fast Plant Total RNA Kit (ZP405-1, Zoman, Beijing, China) and then reversed transcribed into cDNA by a PrimeScriptTM RT Reagent Kit (RR037B, TaKaRa, Kyoto, Japan) following the protocol as previously described [74 (link)]. The RT-qPCR expression was using TransStart® Top Green qPCR SuperMix (+Dye I) kit (AQ132-11, TransGen Biotech, Beijing, China) and an ABI Prism 7500 sequence detection system (Applied Biosystems, Foster City, CA, USA). The list of the primers used in this study is described inTable S2 . β-actin was used as a housekeeping gene [80 (link),81 (link),82 (link)] and it is stably expressed in our material (Figure S3 ). The expression levels were quantified using the 2−ΔΔCt method [83 (link),84 (link)]. Results are represented as the mean ± standard deviation (SD) of three technical and three biological replicates.
Total RNA was isolated from 0.1 g (approximate fresh weight) of sampled soybean seedlings using a Fast Plant Total RNA Kit (ZP405-1, Zoman, Beijing, China) and then reversed transcribed into cDNA by a PrimeScriptTM RT Reagent Kit (RR037B, TaKaRa, Kyoto, Japan) following the protocol as previously described [74 (link)]. The RT-qPCR expression was using TransStart® Top Green qPCR SuperMix (+Dye I) kit (AQ132-11, TransGen Biotech, Beijing, China) and an ABI Prism 7500 sequence detection system (Applied Biosystems, Foster City, CA, USA). The list of the primers used in this study is described in